In the progress of his research on the morphology of Spirochaeta pallida, executed with the help of a stereoscopic microscope, Oelze observed that the spirochete is really spiral shaped, which can be proved by watching it rotate within the observation chamber. The spirals wind clockwise. The last winding, or the apex of the spirochete, is likely to oscillate to the right or to the left. If one end of the spirochete is fixed, its whole body is able to oscillate in either direction. Single parts of a spirochete stretched near its center may oscillate to the right or to the left, but simultaneously in only one direction. On the living spirochete, no flagella are to be observed, a detail important for the microscopic diagnosis of syphilis. In accord with Silberstein, the author states that the use of the live dark field is the most satisfactory method for the recognition of